@article{Matkowski:2012,
  author  = "J. Matkowski",
  title   = "Invariance of a quasi-arithmetic mean with respect to a system of generalized BajraktareviŠ means",
  journal = "Applied Mathematics Letters",
  volume  = "Vol. 25",
  number  = "no 11",
  pages   = "1651--1655",
  year    = "2012",
}